How close is close enough..., Air Fuel Ratio-what kind of numbers do you run? |
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How close is close enough..., Air Fuel Ratio-what kind of numbers do you run? |
computers4kids |
Nov 17 2013, 09:31 PM
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#1
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Love these little cars! Group: Members Posts: 2,443 Joined: 11-June 05 From: Port Townsend, WA Member No.: 4,253 Region Association: None |
I've been playing around with metering rods, springs, and jets for my Edelbrock 600 on my conversion SBC teener, using primarily a vacuum gauge and AEM wideband. I'm currently getting these type of readings
Idle-around 14.5 Cruise Mode--light throttle: 13.7 Power Mode--Heavy Acceleration: 12.3 I'm curious what kind of ratios you carb guys run? The car runs great, but I just wondering if I need to lean the power mode out. The motor likes these numbers and the plugs look good. Also curious, anyone with FI have some numbers available from their wideband? Thanks, Mark Attached image(s) |
ConeDodger |
Nov 17 2013, 09:48 PM
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#2
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Apex killer! Group: Members Posts: 23,611 Joined: 31-December 04 From: Tahoe Area Member No.: 3,380 Region Association: Northern California |
You'll get better mileage with a leaner cruise but if the motor seems happy, that is the right tune... (IMG:style_emoticons/default/smile.gif)
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Mike Bellis |
Nov 17 2013, 09:57 PM
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#3
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Resident Electrician Group: Members Posts: 8,345 Joined: 22-June 09 From: Midlothian TX Member No.: 10,496 Region Association: None |
My idle is 18-23
Cruise 14-17 under boost 8-10 But I'm EFI and turbo. But the engine really likes it! (IMG:style_emoticons/default/evilgrin.gif) |
JRust |
Nov 17 2013, 10:12 PM
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#4
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914 Guru Group: Members Posts: 6,307 Joined: 10-January 03 From: Corvallis Oregon Member No.: 129 Region Association: Pacific Northwest |
My idle is 18-23 Cruise 14-17 I like that ratio. I need to learn my Stinger software. I stay in the 12-14 range but seems a little squarely sometimes. Goes lean on acceleration instead of rich? Not all the time but all I have done is mess with the trims in it. Just need to spend time learning that system & how to adjust the AFR specifically. |
Mike Bellis |
Nov 17 2013, 10:21 PM
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#5
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Resident Electrician Group: Members Posts: 8,345 Joined: 22-June 09 From: Midlothian TX Member No.: 10,496 Region Association: None |
My idle is 18-23 Cruise 14-17 I like that ratio. I need to learn my Stinger software. I stay in the 12-14 range but seems a little squarely sometimes. Goes lean on acceleration instead of rich? Not all the time but all I have done is mess with the trims in it. Just need to spend time learning that system & how to adjust the AFR specifically. That partially why I went with a factory ECU and not a programmable. Way more computing power. (IMG:style_emoticons/default/type.gif) |
brant |
Nov 17 2013, 10:52 PM
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#6
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914 Wizard Group: Members Posts: 11,638 Joined: 30-December 02 From: Colorado Member No.: 47 Region Association: Rocky Mountains |
Water cooled motors like slightly different numbers than air cooled. You would be well served by checking your numbers on the Chevy forums.
Your number for heavy load should really be taken at redline and not just at load |
Andyrew |
Nov 17 2013, 11:09 PM
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#7
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Spooling.... Please wait Group: Members Posts: 13,376 Joined: 20-January 03 From: Riverbank, Ca Member No.: 172 Region Association: Northern California |
You can lean it out a little bit for your primary jets and richen your secondary jets to get cruise closer to 14.5.
I think my idle is dialed in around 17. Anywhere in the 12's is fine for a carb'd SBC at WOT. |
Andyrew |
Nov 17 2013, 11:12 PM
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#8
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Spooling.... Please wait Group: Members Posts: 13,376 Joined: 20-January 03 From: Riverbank, Ca Member No.: 172 Region Association: Northern California |
My idle is 18-23 Cruise 14-17 under boost 8-10 But I'm EFI and turbo. But the engine really likes it! (IMG:style_emoticons/default/evilgrin.gif) Mike, your really between 8-10 at WOT? Wow that is rich. I would have thought they would have tuned it closer to 10-11. Turbo cars Do like to run rich especially modern tuning with lots of timing. But they are literally the experts on that engine... so (IMG:style_emoticons/default/smile.gif) |
Mark Henry |
Nov 17 2013, 11:26 PM
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#9
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
For an air cooled engine you really want to be looking at a cylinder head temp gauge right beside that A/F meter.
If that's a type 4 those readings are good, they need to run richer than a WC engine. |
AfricanHijinx |
Nov 18 2013, 11:29 AM
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#10
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Member Group: Members Posts: 132 Joined: 12-April 11 From: Snohomish WA Member No.: 12,928 Region Association: Pacific Northwest |
I like your dash pad
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sgetsiv |
Nov 21 2013, 09:17 PM
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#11
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Former 914 Owner :( Group: Members Posts: 159 Joined: 20-June 08 From: Portland, OR Member No.: 9,192 Region Association: Pacific Northwest |
I'm just getting started on carb tuning - been running way too rich for the last few years. Currently running 55 idle jets and 150 mains - EMPI HPMX Dual 44mm on my Raby 2315.
I installed an AEM wideband AFR a few months ago and am getting the following readings: At idle - 11.0 to 11.5 Cruising in the 3500-4500 rpm range - 11.5 to 12.5 WOT 2500-3000 rpm range - 10.5 to 11.0 WOT 4000-6000 rpm range - 12.0 to 12.5 Planning to try 52 and 50 idles and 145 and 140 mains over the next few weeks. |
72hardtop |
May 18 2014, 12:28 PM
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#12
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Member Group: Members Posts: 120 Joined: 11-September 13 From: Seattle/HB Ca./Fujieda-Japan Member No.: 16,378 Region Association: Pacific Northwest |
I'm just getting started on carb tuning - been running way too rich for the last few years. Currently running 55 idle jets and 150 mains - EMPI HPMX Dual 44mm on my Raby 2315. I installed an AEM wideband AFR a few months ago and am getting the following readings: At idle - 11.0 to 11.5 Cruising in the 3500-4500 rpm range - 11.5 to 12.5 WOT 2500-3000 rpm range - 10.5 to 11.0 WOT 4000-6000 rpm range - 12.0 to 12.5 Planning to try 52 and 50 idles and 145 and 140 mains over the next few weeks. Your AFR at idle has everything to do with your mixture screws and nothing to do with your idle jets. Your mixture screws are out to far. LBI should be around 13.0. What distributor are you using? Only tune lean (part throttle cruise) if your using a vacuum advance distributor. If your running a centrifugal only distributor shoot for 13.2 (+-.5) across the board. Your too rich WOT. During acceleration 12's are ok but at WOT steady you should be at 13.2 (+-.5) |
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